Previously, hollow core concrete panels have been formed by many methods, including single and multiple pass casting using moving beds and with stationary beds. The hollow cores are made by using slipform extruders that leave core material in place over which concrete is formed. Once cured, the panels are cut to length and lifted and tilted to remove the core material which may be reused.
Some hollow core panels have been made with an insulating layer across the entire surface, as shown in U.S. Pat. No. 4,628,653, the disclosure of which is incorporated herein by reference. Basically, a hollow core panel is cast and interlocking sheets of insulation are laid down before a final pour of concrete. This uniform layer of insulation increases the R-value of the finished wall panels and floor plank.
U.S. Pat. Nos. 4,041,669 and 4,141,946, the disclosures of which are incorporated herein by reference, describe a hollow-core concrete slab in which an inverted U-shaped foam piece is manually placed on a first layer of concrete that is ridged by a screed. The inverted U-shapes define a hollow void that remains after the second pour of concrete is made over the foam.
U.S. Pat. No. 4,369,153 which issued Jan. 18, 1983 to Nash et al discloses a machine which casts hollow core concrete panels in a single casting operation utilizing a slip form technique to fill cores with core material which can be dumped from the core after curing of the concrete has been accomplished. U.S. Pat. No. 4,369,153 is incorporated herein by reference.
In single casting operations, hollow core concrete panels are formed on a moving bed in which concrete is first poured around the front end of a slip form which forms the bottom layer of the concrete panel. The bed moving past the slip form shapes the bottom layer of the concrete panel. As the concrete travels on the bed past the slip form, core material which may be an aggregate is fed into openings in the slip form to fill the desired cores with core material. Alternatively, the bed may be stationary and the slip form may move relative to the bed.
This invention relates to a machine for casting concrete members such as planks and panels, with or without hollow cores. Such beds are typically extremely long and may be 600 feet or more in length. The buildings that house these machines are built to accommodate the machines. The cast panels or planks vary in width according to the maximum width of the machine. Once a factory with machines has been built, it is very difficult to depart from the capabilities of the machines in place due to constraints in the size of the building and the casting beds.
Prior art casting machines have side forms that release and drop away from the beds to remove the cured concrete panels. The existing side forms are dropped down from the bed. Unfortunately, this makes it even more difficult to modify an existing machine to increase the width of the finished panels or plank since additional width must be reserved for the height of the side forms as they drop away.
The art described in this section is not intended to constitute an admission that any patent, publication or other information referred to herein is “prior art” with respect to this invention, unless specifically designated as such. In addition, this section should not be construed to mean that a search has been made or that no other pertinent information as defined in 37 C.F.R. § 1.56(a) exists.